Abstract: A polygonal shaped shield washer for mounting on a pick holder having a mating polygonal shaped barrel, the washer including a top having an interior opening and outer periphery defined by plurality of edges, each pair of adjacent edges being joined at a corner, and a skirt extending rearwardly from the outer periphery of the top, the skirt having a plurality of edges and corners aligned with the edges and corners of the top.

Abstract: A system for extraction of a mineral cutter pick (1), and optionally any interposed sleeve (19), the pick (1) comprises an elongate shank (4) extending from an enlarged head (2), has a piston (12) coaxial with the shank (4), with one end face (16) of the piston (12) subjectable to hydraulic pressure fluid, and with another, opposite end face (15) of the piston (12) capable of engaging an end face (5) of the shank (4), a sealing ring (14) to prevent passage of hydraulic fluid being carried by the piston (12), whereby axial movement of the piston (12), under hydraulic pressure, in turn axially displaces the pick (1), while further movement of the piston (12) results in extraction, if required, of sleeve (19).

Abstract: An assembly is disclosed including a holder block, a cutting pick, and an optional hollow sleeve, wherein the shank of the cutting pick is inserted into the holder block or, where present, into the hollow sleeve. When assembled, surfaces of the components meet at an interface. At least one of the first interface and the second interface includes one or more sets of wear elements including cemented carbide bodies press fit into recesses in the forwardly oriented surfaces meeting at the interfaces. The wear elements mitigate direct contact between the opposing surfaces of the components at the interfaces and prevents excessive wear from repetitive impact because the harder wear elements, e.g., cemented carbide, are contact points between the opposing surfaces of the components at the interfaces. A machine incorporating the assembly and a method of manufacturing the assembly are also disclosed, particularly a machine for mining, excavating, tunneling, road planing and/or construction.

Abstract: A holder block assembly for a drum-type cutting tool has a holder block, a sleeve, and a piston carried in a piston channel formed in the holder block. The sleeve includes a shank and an enlarged flange at an end of the shank. The sleeve shank is received in a hole in the holder block, with the shank and hole wall forming a number of axially spaced interference fits. A source of pressurized fluid applied to the holder block forces the piston against the sleeve to extract the sleeve from the holder block. Sealing structure between the piston and the holder block prevents the release of hydraulic fluid when the sleeve is released.

Abstract: A kicker paddle is disclosed for use with a reclaiming drum. The kicker paddle may have a block with a first end and a second end. The kicker paddle may also have a mounting mechanism located between the first and second ends. The kicker paddle may be symmetric relative to a plane passing through the mounting mechanism that is parallel to the first and second ends.

Abstract: A base block for a cutting drum is disclosed. The base block may have a first end. The first end may have an opening configured to receive a tool. The first end may also have a flat surface surrounding the opening. The base block may have a second end configured to abut the cutting drum. The base block may further have an internal passageway commencing at the opening configured to receive the tool. The passageway may define a longitudinal axis that is offset by an acute angle from being perpendicular to the flat surface.

Abstract: A tool pick assembly and a tool and block assembly are disclosed. A sleeve is positioned about the shank to allow rotation of the tool pick and also friction fit with the block. The sleeve is stepped in complement to the shape of the surface of the shank of the tool pick and the shape of the surface of the bore in the tool holder and extends substantially all of the length, optionally all of the length, of the stepped bore in the block to reduce or prevent dust and fines from entering and wearing the bore surface. When assembled, the stepped sleeve and complementarily shaped shank of the tool pick each do not extend past the rear surface of the bore to mitigate or prevent shank deformation from impact during use.

Abstract: The present invention relates to an interchangeable holder system comprising a basic module and an interchangeable holder for the accommodation of a cutting tool, which interchangeable holder is capable of being attached to the basic module, for the purpose of preparing ground surfaces, and to a construction machine, more particularly a stabilizer, a recycler, or a cold milling machine, comprising a milling device comprising such an interchangeable holder system.

Abstract: The invention relates to a bit holder having an insertion projection and having a bore-shaped bit receptacle that has a longitudinal center axis, a convexly curved support surface being provided on a base part. A bit holder of this kind can be implemented in compact and stable fashion in particular by the fact that the longitudinal center axis of the bit receptacle intersects the support surface.

Abstract: A cutting bit includes an elongate body having a shank portion and a head portion with a forward end. The head portion has an annular channel defined therein adjacent to and rearwardly of the forward end of the head portion. The annular channel has an angled bottom surface. The cutting bit also includes a split wear ring positionable in the annular channel and structured and arranged to be retainably held in the annular channel. The cutting bit further includes a hard cutting tip affixed to the forward end of the head portion.

Abstract: An apparatus for mounting a cutting tool includes a retainer sleeve that defines at least one retention groove adjacent an axial forward end thereof and a washer removably attached to the retainer sleeve. The washer has a forward surface, a rearward surface and an interior surface that define a central opening, wherein the interior surface includes at least one protrusion extending inward into the central opening that is structured and arranged for cooperating with the at least one retention groove in the retainer sleeve. The retainer sleeve further defines a longitudinal slot that extends from an axial forward end to an axial rearward end of the retainer sleeve. The washer further includes a key extending inward into the central opening that is structured and arranged for cooperating with the longitudinal slot in the retainer sleeve.

Abstract: The subject matter of the invention is a bit holder for an earth working machine, in particular a road milling machine, having a support member onto which an insertion projection is indirectly or directly attached on an insertion projection side, the insertion projection comprising at least one convex abutment surface and one pressure surface. In a bit holder of this kind, working forces can be dissipated in stress-optimized fashion into an attached base part when provision is made that the insertion projection comprises two convex abutment surfaces that are arranged at a distance from one another.

Abstract: A road grading pick includes a cutting head, a shank, a shoulder at a transition between the cutting head and the shank, and a polygonal-shaped washer or an oval-shaped washer. The shank is positioned in an opening of the washer to position the washer along a longitudinal length of the shank between a rearward end of the shank and the rearward facing surface of the shoulder. In a preinstalled position, the washer compresses a friction retainer on the shank of the road grading pick to facilitate seating of the road grading pick in a blade of a road grading apparatus. In an installed position on an adapter board for a moldboard of road grading equipment, the friction retainer is no longer in the opening of the washer and the washer prevents washer rotation and shields an underlying mounting surface while allowing rotation of the road grading pick.

Abstract: A cutting tool holding device includes a base, a positioning tube and a positioning member. The base includes a mounting hole and a through hole, and the through hole is formed at a side of the mounting hole and communicated with the mounting hole. The positioning tube includes an axial receiving hole, an accommodated portion and a limiting groove. The axial receiving hole is formed within the positioning tube for receiving a cutting tool. The accommodated portion is disposed at an end of the positioning tube for being installed into the mounting hole. The limiting groove is formed on a side of the accommodated portion. The positioning member is positioned in the through hole of the base, wherein the positioning member abuts against the limiting groove of the positioning tube.

Abstract: A block and sleeve assembly is disclosed including a holder block, and a hollow sleeve. In radial cross-section, outer peripheral edges of the shoulder portion of the sleeve have a shape of a first polygon. The holder block and the hollow sleeve include cooperating rotation inhibiting features. For example, the holder block includes a stop projecting forwardly past a plane of the front face and positioned radially offset from a circumference of the opening in the holder block to allow a rearward surface of the shoulder portion of the sleeve to contact the front face of the holder block and to prevent rotation of the hollow sleeve greater than N degrees, N = 360 n , where n is the number of sides of the first polygon, by contacting an outer peripheral edge of the shoulder portion with the stop. A sleeve per se and an assembly including a cutting pick are also disclosed.

Abstract: A loading arm assembly for directing material removed by a mining machining having a cutting head and a conveyor assembly includes one or more wear resistant plate assemblies at a terminal end of the loading arm. The wear resistant plate assembly includes a wear resistant plate arranged on a surface of arms of the loading arm assembly designed for directing the material to the conveyor. The assembly also has wear resistant inserts along a bottom surface of at least the arm end to protect the bottom surface of the arm from wear as well as the attachment of the wear resistant plate to the arm end.

Abstract: A tool component comprising a wear part covered at least in part by a connection member, the wear part having a specified hardness and the connection member being a metal or alloy, and the wear part comprising a surface that includes one or more depressions or projections therefrom, and the connection member having been pressed against that surface so that at least the surface of the connection member that faces the wear part surface follows the profile of the wear part, whereby relative movement between the wear part and connection member is substantially prevented. The metal or alloy connection member may be readily attached to a tool body for example by brazing of the like. The wear part may comprise a material that is not readily brazeable, for example a ceramic material or a cermet or a superhard material or a composite of such materials.

Abstract: A degradation assembly comprises a rotary portion and a stationary portion. The rotary portion includes a cemented metal bolster bonded to a tip. The tip comprises a symmetric, substantially conically shaped tip formed of diamond and a cemented metal carbide substrate. The stationary portion comprises a holder configured to be coupled to a block mounted to a driving mechanism. A compressible element is disposed intermediate, or between, and in mechanical contact with both the rotary portion and the stationary portion.

Abstract: A bit sleeve for holding a tool bit in a block having a bore that is at least partially tapered, including a collar having a front face for supporting a flange on the tool bit, a flange located rearward of the collar and having a diameter larger than that of the collar, a shank located rearward of the flange and having a diameter smaller than that of the flange, a body adapted to be received into the bore of the block and having a front spherically-shaped portion joined to a rear straight cylindrical portion, a front compression band mounted in a groove in the front portion, and a rear compression band mounted in a groove in the rear portion, wherein when the bit sleeve is installed in the bore, the first and second compression bands are compressed between the body and the bore to secure the sleeve within the bore.

Abstract: Retaining a cutting bit. At least some of the illustrative embodiments are methods including: placing a neck portion of a retaining clip in a groove on outer surface of a sleeve (the sleeve with a cylindrical bore defining a longitudinal axis); then telescoping the sleeve and retaining clip, with the neck portion placed in the groove, within a bit block (the telescoping such that an arm portion of the retaining clip partially occludes an aperture of the cylindrical bore); and then inserting a shank portion of a cutting bit within the cylindrical bore of the sleeve (the arm portion of the retaining clip mates with at least a portion of an annular groove of the shank portion); and retaining the shank portion of the cutting bit by way of the arm portion of the retaining clip.

Abstract: A polygonal shaped shield washer for mounting on a pick holder having a mating polygonal shaped barrel, the washer including a top having an interior opening and outer periphery defined by plurality of edges, each pair of adjacent edges being joined at a corner, and a skirt extending rearwardly from the outer periphery of the top, the skirt having a plurality of edges and corners aligned with the edges and corners of the top.

Abstract: A cutting tool assembly for use in impinging earth strata includes a holder containing a bore having an axial forward end, and the holder having a forward surface surrounding the bore at the axial forward end of the bore. The assembly also includes a cutting tool being rotatably contained within the bore of the holder, and the cutting tool having a rearwardly facing shoulder. The assembly further includes a protective member positionable between the cutting tool and the holder. The protective member has a first surface adjacent the rearwardly facing shoulder of the cutting tool and a second surface adjacent to the forward surface of the holder, wherein the first surface has a first hardness that is greater than a second hardness of the second surface. In one aspect, the second surface of the protective member is in direct contact with the forward surface of the holder. In another aspect, the first surface of the protective member is in direct contact with the rearwardly facing shoulder of the cutting tool.

Abstract: A bit assembly includes a bit having a bit head and a bit shank, a mounting sleeve being held in the region of the bit shank, and a support element that comprises a guidance region being associated with the bit. To allow the bit to be easily deinstalled from the bit receptacle and allow it, if applicable, to be easily installed again, provision is made that the support element comprises, in the region of its underside facing away from the bit head, a deflection segment.

Abstract: An apparatus for mounting a cutting tool includes a retainer sleeve that defines at least one retention groove adjacent an axial forward end thereof and a washer removably attached to the retainer sleeve. The washer has a forward surface, a rearward surface and an interior surface that define a central opening, wherein the interior surface includes at least one protrusion extending inward into the central opening that is structured and arranged for cooperating with the at least one retention groove in the retainer sleeve. The retainer sleeve further defines a longitudinal slot that extends from an axial forward end to an axial rearward end of the retainer sleeve. The washer further includes a key extending inward into the central opening that is structured and arranged for cooperating with the longitudinal slot in the retainer sleeve.

Abstract: In one aspect of the present invention, a degradation assembly has a holder comprising a first end and a second end and a shank with a longitudinal central bore having an opening at an end proximate the second end. The shank portion of the holder has an inside diameter of the bore and an outside diameter wherein either the inner diameter or the outer diameter comprise at least one recess disposed therein which comprises a depth of less than the distance between the inner diameter and the outer diameters.

Abstract: A shank bit, in particular a road milling bit, having a carrier part (10) that comprises a shank (11), the shank (11) carrying a bit tip (18) made of hard material, the carrier part comprising, in the region between the shank and the bit tip, a receiving portion (14) on which a head part is held (30), and the head part comprising a circumferential chip discharge surface (34.1) tapering in a direction toward the bit tip. In order to enable a shank bit of this kind to be designed in wear-optimized fashion, the head part is held rotatably with respect to the carrier part.

Abstract: In one aspect of the present invention, a method of excavation with pointed cutting elements, comprising the steps of providing a excavating assembly with at least one pointed cutting element, the pointed cutting element comprising a rounded apex that intersects a central axis, the pointed cutting element further has a characteristic of having its highest impact resistance to resultant forces aligned with the central axis; engaging the at least one pointed cutting element against a formation such that the formation applies a resultant force against the pointed cutting element; determining an angle of the resultant force; and modifying at least one excavating parameter to align the resultant force with the pointed cutting element's central axis.

Abstract: A holder block assembly for a drum-type cutting tool has a holder block, a sleeve, and a piston carried in a piston channel formed in the holder block. The sleeve includes a shank and an enlarged flange at an end of the shank. The sleeve shank is received in a hole in the holder block, with the shank and hole wall forming a number of axially spaced interference fits. A source of pressurized fluid applied to the holder block forces the piston against the sleeve to extract the sleeve from the holder block. Sealing structure between the piston and the holder block prevents the release of hydraulic fluid when the sleeve is released.

Abstract: A cutting tool assembly including a bit holder having a forward portion, a rearward portion, and a generally planar mounting surface between the forward and rearward portions. The forward portion defines a front aperture having an axis inclined relative to the mounting surface, and the rearward portion defines a rear aperture open to the front aperture. A cutting bit is mounted in the front aperture and includes a rearward end accessible through the rear aperture of the bit holder rearward portion.

Abstract: A quick-change tool holder has an enlarged forward end, a rearwardly extending shank, and an axial bore extending through the enlarged forward end and the shank with the bore having a diameter sized to receive the shank of a cutting tool. A second blind hole extends into the side surface of the enlarged forward end. An extraction device, such as the shank of a worn tool, is inserted into the blind hole. Where the extraction device is a worn tool, the cutting end of the tool is hit with a hammer to remove the tool from a base block mounting.

Abstract: In one aspect of the present invention, a degradation system comprises a driving mechanism. A holder assembly is connected to the driving mechanism. A pick is connected to both the driving mechanism and the holder assembly. At least one predetermined point of failure is configured in the holder assembly to dissipate the force on the pick when the tip of the pick is overloaded.

Abstract: An apparatus can include a base mounted to a mining drum. The base can include an opening including a seat. The apparatus also can include an insert including a bore and an exterior surface. The apparatus also can include a cutter bit including a cutting tip and a shank extending from the cutting tip. The shank can include a threaded portion and a transition positioned between the cutting tip and the threaded portion. The apparatus also can include a retainer including a threaded portion. A portion of the exterior surface of the insert facing the base can be dimensioned to engage the seat of the base. A region of the bore of the insert can be dimensioned to engage the transition of the cutter bit. The threaded portion of the retainer can be configured to engage the threaded portion of the cutter bit.

Abstract: Apparatus for use on a milling or mining drum having a base portion mounted to the drum and a wear insert removably attachable within an opening of the base portion. The opening of the base portion can have a first seat at an upper end and a second seat at a lower end. The wear insert includes a surface configured to engage with the first seat and a bore for receiving a cutter bit at a fixed position relative to the wear insert. A retainer is provided having a threaded portion to engage with the threaded portion of either the wear insert or the cutter bit. The retainer can have a flange dimension to engage with the second seat. The cutter bit can include working end having a pointed geometry having a hardness similar to diamond.

Abstract: A cutting tool configuration for a ground milling machine, for example, a cold milling machine or a mining drill, is provided. The cutting tool configuration comprises a cutter holder, which is fastenable or fastened on a milling drum, a cutting tool, which is fastened on the cutter holder, and which is inserted using its cutting tool shaft in a cutter holder bore of the cutter holder and can rotate around its longitudinal axis, and a wear disc, which is situated rotation-locked between a stop surface of the cutter holder and the cutting tool head of the cutting tool, it being provided that the rotation lock between the wear disc and the cutter holder is caused by at least one groove formed on the outer circumference of the wear disc and a guide formed on the cutter holder and engaging in this groove. A wear disc for use in such a cutting tool configuration, and a cutting tool having such a preinstalled wear disc, are also provided.

Abstract: A retainer for mounting and retaining a rotatable cutting tool or bit in a block bore. The cutting tool contains an annular channel. The retainer has an unstressed diameter greater than the diameter of the bore so that when the cutting tool is inserted into the bore, the retainer expands against the bore so as to be held therein along with the cutting tool. The retainer comprises a cylindrical sleeve having an engaging member extending circumferentially around the sleeve and having a constant cross section shape which projects into the annular channel of the cutting tool and which annular channel has an inward rectangular surface corresponding to the inward engaging member of the retainer for receiving and retaining the retainer to the cutting tool.

Abstract: A cutting tool has a first cutting end, a second cutting end, a shoulder at an interface between the first cutting end and the second cutting end, and a shield removably mounted on one of the first cutting end and second cutting end. The cutting ends each have a cutting tip at a distal end, a body portion, a recess in the body portion and a retainer positioned in the recess. Cutting ends can be mirror images of each other, or may be non-mirror imaged, for example with different gage lengths, to accommodate different operating conditions. One of the cutting ends is mounted in a holder and the shield protects the retainer and recess features on the operating cutting end. A combination of a reversible cutting tool and a sleeve and/or block holder system, an apparatus for cutting, a sleeve per se and a shield per se are also disclosed.

Abstract: A rotatable tool has a tool body that is generally symmetrical about a longitudinal axis, an enlarged cutting head, and a rearwardly extending shank. The shank joins the enlarged cutting head at an annular flange. A compressible sleeve is fitted around the shank and a wear ring is around the shank at the forward end of the sleeve. A disc spring is positioned between the radial flange and the sleeve to remove axial play between the shank and the sleeve and to seal the parts so that hard particles cannot enter and interfere with rotation of the tool.

Abstract: An assembly is disclosed including a holder block, a cutting pick, and an optional hollow sleeve, wherein the shank of the cutting pick is inserted into the holder block or, where present, into the hollow sleeve. When assembled, surfaces of the components meet at an interface. At least one of the first interface and the second interface includes one or more sets of wear elements including cemented carbide bodies press fit into recesses in the forwardly oriented surfaces meeting at the interfaces. The wear elements mitigate direct contact between the opposing surfaces of the components at the interfaces and prevents excessive wear from repetitive impact because the harder wear elements, e.g., cemented carbide, are contact points between the opposing surfaces of the components at the interfaces. A machine incorporating the assembly and a method of manufacturing the assembly are also disclosed, particularly a machine for mining, excavating, tunneling, road planing and/or construction.

Abstract: In one aspect of the invention, a degradation assembly comprises an impact tip brazed to a carbide bolster. A stem protrudes from the bolster, being adapted to be retained within a bore connected to a driving mechanism. A locking fixture is disposed within the bore and locking the stem to a wall of the bore.

Abstract: A system and method to remove quickly an insert, especially an insert with a damaged gripping portion, from a base portion of a mining and/or milling drum. The insert can have a threaded portion engageable with the base portion opening. The insert can define an interior bore configured to receive a cutter bit, and an opening configured to receive an apparatus engageable with the insert opening to facilitate the removal of the insert from the base portion. The insert opening may be polygonal or may include at least one planar surface and/or a rounded corner. An apparatus can engage with the polygonal opening and/or a fastener can engage with the shafted fastener. In both cases, the apparatus and/or fastener is rotated with a force to disengage the threaded portion of the insert from the opening of the base portion.

Abstract: A degradation assembly comprises a rotating portion and a fixed portion. The rotating portion comprises a wear resistant tip bonded to a carbide bolster. The bolster is attached to a shaft adapted for a rotatable connection within a bore of the fixed portion. The fixed portion is adapted for a rigid connection to a driving mechanism. The fixed portion includes an O-ring slot formed within its bore and with an O-ring being disposed therein. The O-ring is at least 15 percent compressed such that the O-ring resists rotation of the shaft.

Abstract: A block and sleeve assembly and a sleeve per se are disclosed. The sleeve has a central bore with a rearwardly opening taper. The holder block has a side-to-side opening with a bridge. An angle of the rearwardly opening taper and/or the distance from the beginning of the taper of the central bore of the sleeve to the surface of the side-to-side opening are sized to allow rearward removal of a shank of a sheared cutting pick from the sleeve. Optionally, an outer circumferential surface of at least a portion of the sleeve shank is forwardly tapered and the opening in the holder block is complementarily tapered to receive the sleeve shank. A rearward biasing retainer clip can also optionally be included.

Abstract: A tool pick assembly and a tool and block assembly are disclosed. A sleeve is positioned about the shank to allow rotation of the tool pick and also friction fit with the block. The sleeve is stepped in complement to the shape of the surface of the shank of the tool pick and the shape of the surface of the bore in the tool holder and extends substantially all of the length, optionally all of the length, of the stepped bore in the block to reduce or prevent dust and fines from entering and wearing the bore surface. When assembled, the stepped sleeve and complementarily shaped shank of the tool pick each do not extend past the rear surface of the bore to mitigate or prevent shank deformation from impact during use.

Abstract: To alleviate the problem associated with wear of either the shank of the cutting pick or the surface defining the cutting pick mounting hole, a cutting pick and mounting assembly is provided including a cutting pick having a shank and a cutting tip, a cutting pick mounting hole extending through a support surface within which the shank of the cutting pick is received such that the cutting tip projects from the hole; an inner sleeve having a cutting pick opening within which the shank of the cutting pick extends; an outer sleeve having an inner sleeve opening within which the inner sleeve and the shank of the cutting pick extend; wherein the shank, the inner sleeve and the outer sleeve are positioned concentrically within the cutting pick mounting hole.

Abstract: An improved bit assembly for road milling, mining, and trenching equipment includes a streamlined tip assembly that is a combination of conical and cylindrical in shape and devoid of protrusions or annular indentations that might impede the flow of removed material over and around the bit assembly or provide space for removed material to become clogged or imbedded on the tip assembly. The generally cylindrical hollow shank that mounts the bit holder to the bit block includes at least one axially aligned slot along its side wall that allows the side wall to bend supply radial force to maintain the bit holder in the bit block.

Abstract: A block and sleeve assembly is disclosed including a holder block, and a hollow sleeve. In radial cross-section, outer peripheral edges of the shoulder portion of the sleeve have a shape of a first polygon. The holder block and the hollow sleeve include cooperating rotation inhibiting features. For example, the holder block includes a stop projecting forwardly past a plane of the front face and positioned radially offset from a circumference of the opening in the holder block to allow a rearward surface of the shoulder portion of the sleeve to contact the front face of the holder block and to prevent rotation of the hollow sleeve greater than N degrees, N = 360 n , where n is the number of sides of the first polygon, by contacting an outer peripheral edge of the shoulder portion with the stop. A sleeve per se and an assembly including a cutting pick are also disclosed.

Abstract: A cutting bit retention assembly (399) that includes a cutting bit holder (500), which receives a cutting bit (58) and has shank (504) that extends into a bore (418) in a support (400). The shank section (504) of the cutting bit holder (500) presents a surface (530) defined by a notch (528) that selectively cooperates with a retention pin (670). A transverse bore (430) in the support (400) carries the retention pin (670). The retention pin (670) is selectively movable to any one of several positions. One position is a non-retaining position wherein the retention pin (670) does not engage the notch surface (530). Another position is a retaining position in which the retention pin (670) engages the notch surface (530) to urge the cutting bit holder into the cutting bit holder bore (418). Still another position is an ejecting position in which the retention pin (670) engages the notch surface (530) to urge the cutting bit holder (500) out of the cutting bit holder bore (418).

Abstract: An improved bit assembly for road milling, mining, and trenching equipment includes a streamlined tip assembly that is a combination of conical and cylindrical in shape and devoid of protrusions or annular indentations that might impede the flow of removed material over and around the bit assembly or provide space for removed material to become clogged or imbedded on the tip assembly. The generally cylindrical hollow shank that mounts the bit holder to the bit block includes at least one axially aligned slot along its side wall that allows the side wall to supply radial force to maintain the bit holder in the bit block.

Abstract: In one aspect of the invention, a degradation assembly comprises an impact tip brazed to a carbide bolster. A stem protrudes from the bolster, being adapted to be retained within a bore connected to a driving mechanism. A locking fixture is disposed within the bore and locking the stem to a wall of the bore.

Abstract: An improved bit holder with its mating bit block is disclosed utilizing a slight taper in the bit block bore, and a tapered shank on the bit holder that includes a second larger diameter tapered distal segment that combines with an axially oriented slot through the side wall of the bit holder shank to allow a substantially larger interference fit between the distal tapered shank segment and the bit block bore than previously known. When inserting the bit holder in the bit block bore, the distal first tapered segment resiliently collapses to allow insertion of that segment into the bit block bore. A second shank tapered portion axially inwardly of the first distal tapered portion. The dual tapered shank allows the insertion of the bit holder in the bit block with an interference fit that provides a secure mounting of the bit holder in the bit block.